Car has no power when accelerating, and now won't accelerate over 25-30mph. When accelerator is "floored" power drops out, but RPMs go up. Check Engine light is on and flashes on occasion.

not enough detail
to get an engine to accelerate , the air /fuel mixture is moved to rich in accordance with engine rpms
the more rpms the richer until the peak rpms are reached
( accelerator pump-power valve in carbies and ECM settings according to accelerator position
black exhaust smoke in diesels
so if you press the accelerator slowly then the air/fuel mixture is altered constantly in relation to the pedal setting
If you floor the pedal then it moves to rich and you get black exhaust smoke until the air mixture is again in balance

Your car acts like it needs a transmission service.That's where you should start. GM cars can act like the trans is shot when all it needs is a new filter. I don't understand how the dealer could miss it, though. Get back to me and let me know.

yes, and check your cable coming from you pedal and up to throtle

my gmc jimmy has that problem in the winter i have to floor it to just move so it tackes a minute to actually move and once im in second gear its fine so just try that

OLD GAS THE NEW GAS THEY HAVE DOESNT LAST MORE THAN 2MONTHS BEFORE IT SEPARATES. YOU PROBABLY HAVE A BAD FUEL PUMP OR ONE THATS ON ITS WAY OUT

If the transmission fluid level is ok then its time for a overhaul.

sounds like the high speed jet in the caburator is fouling,, service the carburator using a kit deigned for your car,,, the kit contains all the replacement parts for the carb..

If the light is flashing it means the engine has a misfire that can damage your catalytic convertor which is very expensive. A tuneup might be in order if its never been done, but I have personally seen many bad timing belts and fuel pumps that have gone bad on those vehicles also.

if the truck feels like,
the more gas you give it the slower it goes,
you might want to check for a converter plugging up.